Hale greeting Arnett's character with "What's up my brother!" was an obvious reference to his popular Arrested Development catch phrase "Hey Brother!". Check out a supercut of all of Buster's (Hale's) "Hey Brother!" moments from Arrested Development below, many of which are directed at Will Arnett's character GOB.
Hopefully Up All Night can get David Cross or Jason Bateman or another one of Will Arnett's Arrested Development co-stars to come on next! And we're only a few short months from Spring 2013, when Arrested Development season 4 will be coming out! Steve Holt!